The present invention relates to fungicidal compositions having a base of metallic alkyl phosphites for the protection of vines, in particular against mildew, as well as a process for the antifungal treatment of vines by means of these compositions.
Fungicidal compositions based on alkyl phosphites which can be employed, in particular, for protecting vines from mildew have been proposed in U.S. Pat. No. 4,139,616 of Ducret et al. The active material of these compositions is described as having a systemic action, in contradistinction to previous antimildew fungicides; that is to say, the active material is carried from its point of application on the leaves to the other parts of the plant by the sap.
More thorough experimentation with these new fungicides on vines has shown that alkyl phosphites provide excellent protection of vine leaves against mildew, i.e. Plasmopora viticola, during the first months of vegetation, but that their fungicidal activity decreases substantially when the leaves become senescent. Thus, starting with the month of August, a progressive invasion is found by mildew on the old leaves, which are generally located at the base of the vine, while the rest of the foliage which has been more recently formed remains protected as a result of the systemic action of the alkyl phosphite based fungicide.
Certain conventional antimildew fungicides of the metallic ethylene-bis-dithiocarbamate type or derivatives of phthalimides exhibit good persistence on the vine but are not considered to have systemic activity.